Active oxygen derived from oxygen generated in the body and oxygen taken in from the lung is present in a body of an animal such as a human. Active oxygen is known to oxidize and damage cells that form a living body while it is necessary for life support. For example, active oxygen, particularly a hydroxyl radical which has the strongest oxidizing power in active oxygen is considered to cause various diseases such as cancer, stroke, myocardial infarction, diabetes, other lifestyle diseases, and skin disorders such as skin aging and dermatitis. Therefore, it is desirable that excess active oxygen, particularly a hydroxyl radical, which has not been used in a reaction useful for a living body, be prevented from being present in the body wherever possible.
Hydroxyl radicals produced in the body are eliminated by reacting with some substances. Hydrogen is known as an example of substances that eliminate hydroxyl radicals. It is water that is produced by hydrogen reacting with hydroxyl radicals, and water does not produce substances harmful to a living body. Thus, a device for producing hydrogen water containing hydrogen which eliminates hydroxyl radicals in the body has been proposed (e.g. Patent Document 1).
However, hydrogen in hydrogen water is easily diffused into air. Thus, for taking hydrogen in the body in an amount necessary for eliminating hydroxyl radicals, it is necessary that the concentration of dissolved hydrogen in hydrogen water be kept high. Therefore, with a method in which hydrogen water is ingested, it is not easy to take hydrogen in the body in an amount sufficient to react the hydrogen with hydroxyl radicals in the body. Thus, for making to easily take hydrogen in the body, a hydrogen-containing composition containing hydrogen and a surfactant has been proposed (Patent Document 2).